A solid-state drive (SSD) including a NAND flash memory (hereinafter, referred to as a NAND memory) has been known as a memory system. In the SSD, relations between a logical address and a physical page are not fixed. The logical address is designated as a reading and writing position by the host. In the SSD, a physical address space corresponding to the physical page is provided and a memory controller provided in the SSD performs the mapping between the logical address and the physical address. The mapping between the logical address and the physical address is recorded in the translation table and is stored in the SSD.